OB 2 stroke maintenance

[rgleason]

I have a Nissan 8 hp 1991-1992 and a Mercury 3.3hp 2005 (I think)
I have cleaned and lubed both, changed the lower unit oil for both, cleaned one carb, lubed the mount bracket and all operating joints.


I have not changed zincs since purchase (They look ok, not corroded much). Is there anything I should do?


Nor have I changed either of the impellers since purchase. They still seem to push water through fine, and I do flush them out, but not necessarily every time they are used.


Is running fresh water through adequate or should I be doing something else?


Should I really change the impellers? How big a job? Will I have to relub the lower unit?


They both run fine now, but I am interested in what is necessary for long term maintenance items. Anything else needed?


Thanks.

[gypsy wanderer]

I own a Nissan 8.8 1993 vintage 2stroke. I can’t give advice on flushing since I have only sailed fresh water lakes. I do recommend changing out the inline fuel filter if it is old. I have motored over 100 miles several times at Lake Powell in Utah. I switched to G-Oil a while back and have been getting better mileage and smoother running engine using this oil. less smoke and smells better too. If you try this only buy the marine type not the weed wacker stuff at Walmart. Amazon has the marine version.
Since you are in colder climate in Boston don’t do like me and delay draining water from lower leg come Fall. Hope any of this helps.
Don

[a64pilot]

Usually changing an impeller is dead easy, disconnect the shift linkage, then usually four bolts and the whole foot comes off, there are several youtube videos of it, likely one for your engine.
After five years I finally changed mine this year. Other than a set being taken by a couple of blades from sitting bent over I’m sure, you could see no wear or deterioration. On my Suzuki the blades don’t have to bend over as far against the center hub as they do on my Yanmar so I think it would outlast it.
I changed mine just because it had been five years, how long can a piece of rubber last? It was working fine before the change, and likely had years left, who knows?

Anyway if you change yours be sure to grease or antisense the bolts as they are SS being screwed into aluminum and may be there for years, and put grease on the driveshaft splines before you put it back together. I’ve never had one seize, but it’s my understanding that if it does that can be the end of the motor as there is no way except force to get it apart.
A large part of why I changed it was to get the engine apart, being afraid if I let it go many years that maybe you couldn’t get it apart.
I take the prop off every year and grease the splines cause one time I had one seized, and the foot ended up having to be replaced after a torch etc was tried without success.

[a64pilot]

You do not have to drain the foot to change an impeller, the foot is sealed, you can position it anyway you like no oil will spill.

If your in fresh water your zincs will last forever, you need Magnesium anodes.
I’m 99% salt water and have gone over to aluminum anodes, the work if both fresh and salt and I believe work better.

I have never flushed an outboard with anything but drinking water from a hose and have never had a problem of any kind. I have seen others use salt away etc, but I think they are wasting their money.

[Lake-Effect]

Originally Posted by a64pilot

Usually changing an impeller is dead easy, disconnect the shift linkage, then usually four bolts and the whole foot comes off, there are several youtube videos of it, likely one for your engine.
After five years I finally changed mine this year. Other than a set being taken by a couple of blades from sitting bent over I’m sure, you could see no wear or deterioration. On my Suzuki the blades don’t have to bend over as far against the center hub as they do on my Yanmar so I think it would outlast it.
I changed mine just because it had been five years, how long can a piece of rubber last? It was working fine before the change, and likely had years left, who knows?

We have an old suzuki 5 HP. Like yours the impeller still seemed in great shape with no cracks or wear, so I'm staying with it. If the engine still pees and doesn't overheat, I'm happy.

The lower leg came off ok, but aligning the shift linkage when assembling and getting it tight enough was a pain. It took a few tries. The best I could come up with was to set the shifter and the lower unit to "forward" before tightening the clamp.

I've changed the lower unit oil once... the stuff that came out was as clean as the new lube I put in, and no water, so I don't worry alot about it either.

Other than that... clean and gap the plugs, fresh gas and good 2-stroke oil... the thing starts first or second pull every spring and runs smoothly and reliably.

[tkeithlu]

Run it dry before you put it away for the winter. You don't want to have to pull that rope until the old non-volatile gas is out of the carb next spring.

[rgleason]

All good advice here. I think I'll look for video, and also remove the prop and grease that, the spline and all ss bolts etc. First I've got to order the impeller and both gaskets?

Knowing I dont have to do the lower unit lube again helps! Thanks

[a64pilot]

I’m not sure which gaskets you speak of, on my Suzuki there are two wear plates that have gaskets and you can buy them in a water pump kit for I think $4 bucks more than just the impeller, so I bought the kit, but only used the impeller.
On my Mercury Verado I don’t remember any gaskets either, but it if your motor has them by all means order them too. In both cases I kept the old impeller for a spare just in case something happens.

[Cheechako]

Run it dry end of use.
Fresh water flush.
The most important maintenance is run it , run it, run it... often!

If you can get non ethanol gas do it! Farm supply etc have it. Some states Union 76 sell it.

[rgleason]

After cleaning the carb twice, I got a kit and rebuilt it. There was still a problem with the high speed adjustment. Intermittant cutting out, but not ignition because I got an ignition indicator and that seems fine. Sometimes the fuel blockage works its way out. Lawnmower guy said sometimes gunk in the high speed orifices is very hard to get out.

I have put carb cleaner and mechanic in bottle in gas. The problem gets fixed then comes back. It might be due to the high speed needle sticking and not responding. The needle itself is new

I am going to remove all the gas (I filtered it), install new fuel line hoses (small pieces of rubber getting loose?) and put in a small inline filter in addition to the very small one in the tank. Any other ideas?

I've replaced the water pump impeller and although all the blades were there it was stiffer and mis-shapened after many.years of use. Greased all the bolts. Pisses the same.

[Compass790]

I reckon the inline fuel filter it the most important thing you can do for a small outboard. Recommend to always use a filter funnel as well for all engines actually.
Next thing is clean the kill switch & spray with whatever CRC variant you like as they are another thing to give trouble if anything does.
Cheechako got the other secret too.

[GordMay]

OUTBOARD MOTORS LEARNER’S GUIDE FOR PACIFIC ISLAND MARINERS
Covers: Operation, Troubleshooting, and Maintenance.
➥ http://coastfish.spc.int/Sections/tr...oard_lg_en.pdf

[rgleason]

Well it does have a very small inline filter at the shutoff, that I found loose in the tank and put it back on. But it is still misbehaving. So will change the gas ane fuel lines and add another filter. Something has changed after 2003-2019 16 years with little to no problems.

[Thumbs Up]

I also have a Nissan/Tohatsu 8, 2 stroke. the factory service manual recommends completely disassembling the entire engine yearly to clean out the carbon deposits. Nobody ever does this though. I did have it apart once and there was hardly any carbon deposit at all. The single best improvement I have ever made to it was replacing the main jet in the carb. It is not included in the rebuild kit. These jets erode over time and cause the engine to run way to rich. Or buy an aftermarket carb for it, they are pretty cheap. I have used this engine for many years, would rather have the 9.8 which is the same engine with more power. These are the best small outboards made! Very hard to destroy. Clean the threads on the clamps with a knife blade every year or they will seize. A bad bowl gasket can cause flooding. Most of the problems are from running too rich not too lean. Are your plugs black and sooty or wet? Before I changed the jet, gunk in the bowl sometimes made it run better. Make a spark gap tester to rule out an electrical problem. Both plug wires should be able to jump a 1/2" gap simultaneously. You need to do this test in low light. And start with fresh gas/oil mix. You might think that no water is in your tank but it might have water in it. You can buy a threaded flush fitting but I could never get the plug off so I never used it. You should run it in fresh water any chance you get.

[rgleason]

Thanks everyone, good suggestions. I purchased new gas line and inline filters at the lawnmower shop. The 1/4" gas line is just a little big, so I cut the original gas line and inserted the inline filter. The engine now starts and runs fine. I can now accelerate to higher rpm without the engine choking up, and it is responsive.

Now I am thinking it is a little rich, and I can adjust the low speed needle, but how does on adjust the high speed there is no screw adjustment?

So perhaps it is gas with some dirt in it and the other filter is not doing its job. I haven't changed the gas yet, but it is 60% new gas and 40% late last year.

I am going to have to get the new smaller gas line from merc I guess.


The routine maintenance of clamps and greasing SS bolts and tilt bolts, etc and flushing in fresh water is all necessary for long term use. This spring I did have to do a big clean and grease job on all the moving parts, including replacement of the rusty bolt connecting the brackets.